Blasting cap



June 25, 1935. RQSENTHAL 2,005,957

BLASTING CAP Filed June 18, 1934 INVENTOR.

ATTORNEYS.

-- ant-5.9a 1 BLASTlNG CAP m a 1s i Mercer;

. lApplica'tion Junels, 1934, Serial ism-731,045

. solem (o1. 102 s) 1,

invention relates td blasting caps or fuse caps containing explosive compounds as 'used for detonating 'dynamiteand other high" explosives,

I and the objects fo'f the invention' a'reto provide improvements, in -such caps which will reduce the percentage"of 'misiiresto which such caps are nowfsubjeCt.

In thedrawing 'a'cc t fi ures owL r Fig: lfa longitudinal section of regular ex plode'r cap withfus plaice.

P eri is r ie i "Fig; 2; a longitudinal sectionof afuse and cap combination; similar totthat of Fig; l but showing" 1 the explosive formed' with 'a grooved surtaceQ' Fig.--3 is a cross section of Figkzas seen from theline 3- -3 of Fig 2;- 3

V Fig. 4, a1 longitudinal{sectionof "a cap and its charge of 'fulminate or-thelike formed with a surface grooved in across directions.

Fig. 5, a cross section of Fig. 4 taken along the'line 55 thereof. 1

Fig. 6 is a viewof a blasting cap similar to that of Fig 4 but showing a still further modification of the surface formation of thedetonating compound. I

Fig. 7 is across section the line 'l 1 thereof.

ofFig. 6 taken along Fig. 8 is a view similar to that of Fig. 4 but shows the compound formed on its surface with but one central protuberance, I

Fig. .9.is a view of a blasting cap similar to that of Figs; 4 or 2' but with the side, wall of the 1 'point adjacent the compound 3, generally a mercury fulminatemixture compressed tightly into the shell by means of a smallpress plunger rod, not shown in the drawing, while into this shell projects a fuse 4 of conventional construction carrying an'internal powder train 5. 'I'he' fuseiscut off straight, or,

'cies, to seal the joint when desired to prevent any i'nserted andi c'rimped in V which may form. rather, at right angles at its inner end so as to possibility of water getting in when thefuse is} used in damp places. In such fuse and cap combinations-it is found difii'cult to insure the end di -the fuse orpowden train 15' contacting the fulminate othe'rfiexplo sive'compound 3 in amanner to'insure firing, and if *aKslight space exists between these elements of the combination, gases may accumulate as the fuse burns .down intot he shellrandbuild upa' pressureat tliispoint so that the advancing flame 10 is raises bacl'g: and/or; thefuse itself may; be forced backslightly 1 or the pressure of I spent; w gases puts the fire out. Just what is the precise cause of the} failures frequently "metwith' may 1 not beknownbutit isobviously due to one 'or 15 more'of-the reasonsabove givenfa'nd it is to avoid suc'hfiring failures-and the lds's' of effectiveness of a blast wheresveralholes must be shot in} succession, together with the great danger attendant upon having unexploded charges to con- 2 tend-with, that my improvements have been worked out. 7 V

The principal feature of, my invention is; the provision of a grooved, slotted, corrugated, or Otherwise roughened, surface'onthe detonating 7 compound to afford lateral passage for the gases should they accumulate, either for escape of the I gas along the sides of the fuse if not crimped too tightly, or for compression within the groove or grooves while still permitting the'fusetrain to remain in contact with at least one or more raised points of the compound. I

In Figs. 2 and '3 the grooving of the surface of the detonating compound takes the form of simple parallel grooves l. 1

In Figs. 4 and 5 the grooves 8 are arranged, as two pairs in crossing relation; 1

In Figs. 6 and 7 the grooves 9 are arranged radially while preserving a small central nucleus In which would impinge the powdentrain. 40

. In' Fig. 3 the central nucleus of Fig. 6 has been exaggerated into a rounding-central lump [2 adapted to be almost forced into the powder train when the fuse is pushed into the cap even though. the train should be retracted somewhat from loss of powder, and'still preserve a circular passageway for escape of or, compression of gases In Fig. 9a still further modification shows the surface of the detonating compound corrugated or grooved, as in Fig. 2, to present little ridgesor elevations to the flame of the fuse, and this View also shows a localized outward bulge .i l adjacent-the surface of the compound 3 which provides a pocket in whichthe gases may compress while still leaving the fuse incontact with one or more ridges of the compound. The bulged portion l I may extend as a ring around the shell, or go but part way around, or may be a series of bulges, and there may be any number of large or small bulges around the shell for the purpose set out. w a

In forming the slots, corrugations, ridges, or elevations, on the surface of the compound the punch used to force the material into the cap shell is simply made in counterformto thedesign of surface modeling desired, and thus it entails no more labor to have the surface formed in any of the designsshownthan to use a plain nosed punch. 5

It is, of course, apparent that while I have shown the grooves, ridges, etc.-,- arranged in a ;,regular pattern, this is not necessarilyso as the undulations or protuberances maybe of an, irregular pattern if desired. It is,'however, de sirable; that the small indentations and protuberances be more or less rounded at theiredges to avoid the danger of I small particles of the compound becoming chipped off or dislodged.

Having thus described my improved construction in blasting caps, what I claim is; I

1. A fuse cap comprising a shell containing a quantity of a detonating compound compacted into one end and presenting a surface adapted to contact the end of the powder train of, a

fuse inserted into the shell, and'sai d surface of the compound formed with a gas escape'channeh leading to the wall of theshell. Y

2. A fuse cap comprising a shell containing a quantity of a detonating compound compacted into one end, and the surface of the compound formed with grooves and ridges, said grooves extending-to the wall of theshell.

3. A fuse cap comprising ashell containing a,

quantity of a detonating compound compacted into one end, and the surface of the compoundformed with grooves and ridges in crossing arrangement. 1 a

4. A fuse cap comprising a shell containing a quantity of a detonating compound compacted into one end, and the surface of the compound formed with a central protuberance adapted to impinge the powder train of a fuse inserted in the shell, p r v V r 5. A fuse cap comprising a shell containinga quantity of a detonating compound compacted into one endand against which compound the end of a fuse inserted in the shell is adapted to, "contact, and an outwardly bulged pocket in the shell wall providing a receiving space for accumulated gas of fuse combustion.

6. In a construction as specified in claim 5,

said outwardly bulged pocket in the shell wall extending substantially around the same.

I. A fuse cap comprising a shell containing a quantity of a detonating compound compacted into one end and. against which compound the,

end of ,thepowder train of a fuse inserted in the shell is adapted to contact, a pocket formed in the surface of the compound adjacent the end of the fuse adapted for receiving'a small amount I of gas under pressure, and a pocket for similar purpose formed in the shell.

8. A fuse capv comprising. a shell containing a quantity of. a, detonating compound compacted into one end and'against which compound the endof the powder train of a fuse inserted in the shell'is adapted to contact, a pocket formed in; the surface of the compound adjacent the end:

of the fuse adapted for receiving a small amount of gas under pressure, and an annular pocket- 7 for similar purpose formed in the shell. g

FRANK ROSENTHAL. 

